You are giving them 180 days...1/2 a year for them to file any complains against your firm that have arise from your work?
That is way too long. Imagine figuring who broke a sprinkler component 1/2 a year ago. It will be a nightmare for you.
Shorten it to 60 days.....basically they can still sue you but after 60 days the judge might see it a little bit your way because time is working against them.

Secondly, there is a clause for non-assignment that basically limits your rights to NOT sell this contract. Why would you want to do that?....one day you might want to sell your business and you will be at your customers mercy. Don't let them assign the contract to someone else but leave it open for you to be able to sell it.